Linux pvops ballooning pv only?

Linux pvops ballooning pv only?

[Dan Magenheimer]

I was just looking at the Linux upstream balloon driver
and noticed that balloon_init fails if !xen_pv_domain().
Why does ballooning not work for an HVM domain?  Is
ballooning just missing or untested functionality for
HVM, or is there a good technical reason why it won't work?

Thanks,
Dan

RE: Linux pvops ballooning pv only?

[AP Xen]

Ballooning does work for HVM domains. I applied Alex Bligh's patch
(http://blog.alex.org.uk/archives/23) to the stock Ubuntu 10.04 64-bit
kernel and was able to balloon up and down. There does seem to be an
accounting bug that I am debugging. The check you are talking about is of
course not present. It would be a shame if the upstream driver had that
check :(

Thanks,
AP
> -----Original Message-----
> From: xen-devel-bounces@lists.xensource.com [mailto:xen-devel-
> bounces@lists.xensource.com] On Behalf Of Dan Magenheimer
> Sent: Monday, June 14, 2010 10:12 AM
> To: Xen-Devel (xen-devel@lists.xensource.com)
> Cc: Jeremy Fitzhardinge
> Subject: [Xen-devel] Linux pvops ballooning pv only?
> 
> I was just looking at the Linux upstream balloon driver
> and noticed that balloon_init fails if !xen_pv_domain().
> Why does ballooning not work for an HVM domain?  Is
> ballooning just missing or untested functionality for
> HVM, or is there a good technical reason why it won't work?
> 
> Thanks,
> Dan
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel

Re: Linux pvops ballooning pv only?

[Jeremy Fitzhardinge]

On 06/14/2010 06:12 PM, Dan Magenheimer wrote:
> I was just looking at the Linux upstream balloon driver
> and noticed that balloon_init fails if !xen_pv_domain().
> Why does ballooning not work for an HVM domain?  Is
> ballooning just missing or untested functionality for
> HVM, or is there a good technical reason why it won't work?
>   

I think its just there to prevent balloon from activating on native.  I
suspect the test could be xen_domain(), but it may need other changes to
handle the details of adding/removing pages...

    J